Comment by DavidWoof

I've always established the team rule that most PRs must be reviewed within a day. At the very least, devs should be reviewing any open PRs before they leave or when they first get in.

Obviously, there's going to be exceptions for large changes or big rewrites on the one hand, or for tiny label changes on the other hand.

PS. Reading the comments here, people seem to work in some pretty dysfunctional environments. Get the team together and establish some guidelines that everyone agrees on. Review time should be predictable, and the work should be reasonably shared.